Throttle Body Advice
 

I installed larger Holly injectors in my 500efi intakes. Engines are 540's. A/F went way rich which I was able to get back to mid 12's by turning the fuel pressure down into the mid 20's. Suprisingly it runs pretty well with FP that low but I'm looking for a more permenant solution. I of course plan to have the ECU's reprogrammed again but am also thinking about installing larger throttle bodys from ASM or TPIS. Anybody have an opinion on if that will be worth the money HP-wise or which monoblade is better? As far as I can find, those are the only 2 aftermarket monoblades out there for the 500efi. If anyone knows of any others or other options I'm all ears (or eyes).

Always have to reprogram for injector size change. Fuel psi is one dimensional. Okay, within reason, if you just need a 1 dinensional change.

what if I boat in the 8th dimension.:D

Try drug rehab ? Lol :wink

Heres the facts on throttle bidys and flame arrestors, on my dyno a stock 500 loses about 8 hp with stock FA off, a sightly modded one loses 15 to 20 hp. With a cam change, heads or head work, they gain about 12 to 15 hp with a AZSM tb w intake modded, same with small one tpos sells and also by putting a 525 tb and plenum on. The gain will be bigger with a 540. Tpis sells a bigger yet tb which is well suited for a modded 540 BUT its a crazy amount of work to use it. You have to weld a adapter to plenum amd do a extreme amount of grinding plus theres no orovisiin for IAC so it has to be relocated. On the.modded engines, a 525 FA or a hardin billet poses virtually no restrictiin BUT, they dont clamp . On, they bolt on so you have to mod face of the azsm to use it. Both small ones will require you to cut/grind the plenum to work, not a big deal. IF you buy the AZSM , mod plenum but then put the restrictive 500 efi FA on, you will kill most your gains.. i have rescaled and tuned slightly modded 500s for holley 48 lb injectors so depending where your at and how you.plan on retuning it, i may be able to offer.help there, Smitty

Thanks Smitty. I'm not looking to make this the kind of project you describe to use the 525 TB or the larger TPIS so I'll probably go with the smallerTPIS inasmuch as it about $50 cheaper than ASM. What do you charge for the reprogram, or does that deopend on how much you need to twiddle with it? How do you do it- I send you a series of A/F and Mfld vacuum #s at various RPM's along w/ the ECU's?

nice speaking with you on phone. Something i forgot to ask, are you still running the stock 210 lph fuel pumps, since its running rich, sounds like theor keeping up but that 580 hp area with BSFCS in the .55, .58 range is whete their about maxed out. Do you have fuel pressure gauges, smitty

I'm using the stock pumps but also have low pressure lift pumps. Don't know if that's helping them keep up? I'll call you next week.
Thanks again-